Surgical instruments are used, for example, for clamping and closing, as well as, optionally, for severing clamped and closed blood vessels. Such instruments have been disclosed in, for example, DE 298 04 860 U1, U.S. Pat. No. 5,984,939, US 2010/0234687, WO 2010/009525 A1, DE 10 2010 040 667 A1, WO 2004/091377 A2, WO 97/41783, US 2009/017147 A1, WO 2008/020964 A2 and U.S. Pat. No. 5,855,590. The disclosed instruments, most of them being provided for laparoscopic or endoscopic use, commonly comprise an elongated shaft that extends away from a grip. Attached to the distal end of the shaft is a tool that can be moved, via an actuating device, with the use of the grip. A transmission mechanism establishes a driving connection between the actuating device and the tool. The transmission mechanism is e.g., a pull wire that extends through the tubular shaft. Naturally, a certain play must exist between the pull wire and the inside wall of the shaft to ensure ease of movement of the pull wire.
Surgical instruments are used in a moist environment. If moisture such as, for example, tissue fluid of any type, rinsing fluid or the like, enters a surgical instrument, this can result in electrical or other malfunctions. This is at least true for single-use surgical instruments. In multiple-use surgical instruments, it is also possible for fluid to enter the housing during the sterilization processes needed between different uses, which can cause failures in the housing.